Cystic fibrosis (CS) is a generalized exocrinopathy in which the basic defect is still unknown. Studies have been pursued to determine the characteristics of the disease which are primary and related to a gene defect rather than secondary manifestations. Nutritional assessment of the patients has shown the majority of subjects consume an inadequate number of kilocalories per day to meet their energy requirement and that this observation holds true independent of their degree of pancreatic involvement. Methods of improving nutrient intake have included nutritional counselling and a clinical trial using cimetidine. New diagnostic methods of evaluating the degree of pancreatic insufficiency have been investigated. Ultrasonography has been used to evaluate abdominal organs as well as cardiac changes which accompany progressive pulmonary disease of CF. These new aids in diagnosing clinical features of CF are especially useful since they offer non-invasive techniques for following longitudinally such functions as cardiac, pancreatic and possibly liver involvement in the CF patient.